南海南部浅表层柱状沉积物孔隙水地球化学特征对甲烷渗漏活动的指示

海底沉积物孔隙水地球化学特征能快速响应甲烷渗漏活动及其生物地球化学过程,从而记录甲烷渗漏活动特征。对采自南海南部北康盆地的3个重力沉积柱状沉积物孔隙水样品（BH-H75、BH-H13Y和BH-H61）进行了甲烷浓度、溶解无机碳（DIC）和碳同位素（δ13CDIC）、阴离子（SO42−、Cl−）以及主微量元素（Ca2+、Mg2+、Sr2+、Ba2+）等地球化学分析。（△DIC+△Ca2++△Mg2+）/△SO42−比率图解与δ13CDIC深度剖面特征揭示了有机质硫酸盐还原反应（OSR）和硫酸盐驱动-甲烷厌氧氧化反应（SD-AOM）在不同沉积柱中所占比例的不同,其中BH-H13Y沉积柱中OSR和SD-AOM共同存在;BH-H75沉积柱中OSR占主导;在BH-H61沉积柱中SD-AOM占主导,且其底部可能存在微生物产甲烷作用。硫酸盐浓度线性拟合关系指示BH-H13Y的硫酸盐-甲烷过渡带（SMTZ）的深度约为700 cmbsf。结合SO42−浓度、DIC浓度最大值和δ13CDIC最小值推测BH-H61的SMTZ深度约为480 cmbsf。BH-H61和BH-H13Y沉积柱中,较浅的SMTZ深度、上升的DIC浓度以及强烈负偏的δ13CDIC值指示研究区存在甲烷渗漏活动。此外,在BH-H61和BH-H13Y站位,硫酸盐浓度随深度降低的变化梯度在沉积柱下部较上部陡,指示向上迁移的甲烷通量在时间上逐渐增强。孔隙水中Ca2+、Mg2+、Sr2+浓度以及Mg/Ca、Sr/Ca比值变化特征指示研究区沉积物中可能有自生高镁方解石矿物生成;而BH-H61站位SMTZ界面以下,孔隙水中Ba2+浓度升高,指示了硫酸钡的溶解作用。     

区际贸易隐含碳排放转移研究进展与展望

区际贸易隐含碳排放转移是导致区际碳泄漏、碳减排权责失衡等问题的重要原因,对全球碳排放格局及碳减排效果影响重大。研究区际碳转移时空格局演化规律和内在驱动机理,研制针对性碳转移优化调控方案,对提升区域整体碳减排效率和经济生态综合效益,具有重要现实意义,近年来已引起了国内外学者越来越多的关注,逐渐成为区域可持续发展和生态经济研究的热点问题之一。本文对国内外区际碳转移的相关研究成果进行了梳理,重点总结了对中国省际隐含碳转移问题研究的进展和成果应用情况,展望了区际贸易碳转移问题未来研究的方向：进一步重视国际、省际碳排放转移间的协同研究,揭示区际碳排放转移的动态驱动力及驱动机理,探索创新基于共同责任的省际碳转移减排机制等。     

Deep groundwater circulation and associated methane leakage in the northern Canadian Rocky Mountains

Concern over potential impact of shale gas development on shallow groundwater systems requires greater understanding of crustal scale fluid movement. We examined natural deeply circulating groundwater systems in northeastern British Columbia adjacent to a region of shale gas development, in order to elucidate origin of waters, depths of circulation, and controls on fluid flow. These systems are expressed as thermal springs that occur in the deformed sedimentary rocks of the Liard Basin. Stable isotope data from these springs show that they originate as meteoric water. Although there are no thermal anomalies in the region, outlet temperatures range from 30 to 56 °C, reflecting depth of circulation. Based on aqueous geothermometry and geothermal gradients, circulation depths up to 3.8 km are estimated, demonstrating connection of deep groundwater systems to the surface. Springs are also characterised by leakage of thermogenic gas from deep strata that is partly attenuated by methanotrophic microbial communities in the spring waters. Springs are restricted to anomalous structural features, cross cutting faults, and crests of fault-cored anticlines. On a regional scale they are aligned with the major tectonic features of the Liard Line and Larsen Fault. This suggests that while connection of surface to deep reservoirs is possible, it is rare and restricted to highly deformed geologic units that produce permeable pathways from depth through otherwise thick intervening shale units. Results allow a better understanding of potential for communication between deep shale gas units and shallow aquifer systems.     

Reflecting on the risks and ethical dilemmas of digital research

As technology continues to evolve, digital methods are increasingly becoming key components of social and cultural geographers’ research toolkits. This paper explores the risky and uncertain dimensions of digital research by reflecting on an adverse ethical event which occurred in research involving young people and online dialogic diaries. Assemblage thinking is used to conceptually frame the data leakage event, the subsequent disruption of confidentiality, and the wide-ranging affects and effects that followed. Three particular issues which are critical for researchers working with digital methodologies to consider are highlighted: the ethical implications of procedural disruption, institutional responses within the neoliberal university, and researcher wellbeing. We conclude by advocating for researchers to continue to push boundaries with digital research but suggest that this needs to be undertaken in an informed way that takes account of the immanent potential for digital disruption.     

Improved Arctic Ocean Mass Variability Inferred from Time-Variable Gravity with Constraints and Dual Leakage Correction

Abstract

The ocean mass variability inferred from Gravity Recovery and Climate Experiment (GRACE) satellites mission is challenged by the stripes and the leakage across land-ocean boundary. The recently released GRACE mascons solutions are advanced by applying constraints that remove efficiently the stripes and dual leakage correction that restores the coastal ocean mass variability. Here we quantitatively evaluate the improvement in the Arctic Ocean mass variability by GRACE mascons. To do so, we compare the combination of GRACE solutions (including the mascons solutions and traditional spherical harmonic coefficients (SHCs) solutions) and the steric estimates against the altimeter observations. Our results suggest that mascons solutions produce stronger correlations compared to SHCs solutions, especially along the coastal zone, indicating the importance of the dual leakage correction. Stronger correlation is produced by the mascons over a small basin in the interior of the Arctic Ocean, suggesting that mascons solutions deliver better ocean mass variability than the SHCs solutions. Since the comparisons are carried out over two sub-basins, we conclude that mascons are able to provide better regional ocean mass variability that may have implications for regional sea level budget, in particular over the coastal zone.     

Groundwater response to tidal fluctuations in a leaky confined coastal aquifer with a finite length

The study on the hydraulic properties of coastal aquifers has significant implications both in hydrological sciences and environmental engineering. Although many analytical solutions are available, most of them are based on the same basic assumption that assumes aquifers extend landward semi‐infinitely, which does not necessarily reflect the reality. In this study, the general solutions for a leaky confined coastal aquifer have been developed that consider both finitely landward constant‐head and no‐flow boundaries. The newly developed solutions were then used to examine theoretically the joint effects of leakage and aquifer length on hydraulic head fluctuations within the leaky confined aquifer, and the validity of using the simplified solution, which assumes the aquifer is semi‐infinite. The results illustrated that the use of the simplified solution may cause significant errors, depending on joint effects of leakage and aquifer length. A dimensionless characteristic parameter was then proposed as an index for judging the applicability of the simplified solution. In addition, practical application of the general solution for the constant‐head inland boundary was used to characterize the hydraulic properties of a leaky confined aquifer using the data collected from a field site at the Seine River estuary, France, and the versatility of the general solution was further justified.     

Use of stable water isotopes to assess sources and influences of slope groundwater on slope failure

This study employs stable oxygen and hydrogen isotopes as natural tracers to assess the headwater of a landslide next to a drainage divide and the importance of the slope's headwater in the study area. The study is undertaken near Wu‐She Township in the mountains of central Taiwan. Because a reservoir is located on the other side of the divide, this study evaluates the relationship between the reservoir water and headwater of the landslide as well. Over a 1‐year period, water samples from September 2008 to September 2009, including local precipitation (LP), Wu‐She Reservoir's water (WSRW), slope groundwater (SGW), upper‐reach stream water (USTW), and down‐reach stream water (DSTW), were analysed for deuterium (δD) and oxygen (δ¹⁸O) stable isotopes. Results indicate that WSRW is the predominant component in SGW: approximately 70% of SGW originates from WSRW and 30% from LP based on a two end‐member mass‐balance mixing model for δ¹⁸O. The similar two end‐member mixing model is also employed to assess the contributions of USTW and SGW to DSTW. Model results indicate that SGW is the major source of DSTW with a contribution of about 67%. Accordingly, about 47% of DSTW sources from the WSRW. In short, owing to reservoir leakage, WSRW contributes the greater part of both SGW and DSTW. Plentiful WSRW in SGW threatens the stability of the slope in the divide area. To avoid subsequent continuous slope failure, necessary mitigation steps are required. Copyright © 2011 John Wiley & Sons, Ltd.     

富水管道型岩溶隧道衬砌结构力学响应特征研究

对于围岩中存在管道型溶腔的岩溶隧道而言,受地表强降雨及地下水的影响,管道型溶腔内极易积聚高水压力,进而引发衬砌开裂、渗漏水及涌水病害。为了探明管道型溶腔中高水压力对衬砌结构的影响,开展了富水管道型岩溶隧道衬砌结构力学响应模型试验,对不同溶腔位置及不同水头高度影响下的衬砌结构内力特征进行了研究。基于此,建立扩展工况的数值计算模型,进一步探究了不同溶腔直径、溶腔位置及溶腔水头高度对衬砌结构内力的影响。结果表明：当隧道周围存在管道型溶腔时,与溶腔接触位置的衬砌内侧承受较大的正弯矩,为衬砌结构的最不利受力位置;随着溶腔直径和溶腔内水头高度的增加,衬砌内力显著增大;溶腔所在位置影响着衬砌内力的分布,当溶腔位于隧道拱顶时,衬砌结构的抗水压能力最小。研究结果可为管道型岩溶隧道的结构设计及安全施工提供借鉴。     

渤海海域多期伸展型交汇断层封闭性评价方法

渤海海域新生代经历了复杂的多期伸展运动,导致交汇型断裂系统异常发育。交汇型断层控制的断块圈闭已经被证明是重要的油气聚集区,但是大量的勘探实践表明交汇断层的油气渗漏程度是成藏差异性的主要原因。综合利用钻井资料、三维地震资料和构造物理模拟技术对交汇断层的封闭性进行研究,结果显示：（1）交汇断层发育演化程度控制了交汇点渗漏强度;（2）油气充注—渗漏相对时间控制了交汇断层的有效封闭时间;（3）早期先存断裂的斜向拉伸作用导致的不同走向断层的应力差异影响断层封闭能力。综合利用上述三个影响因素对渤海油田交汇型断层实钻构造的封闭性进行了模糊综合评价,发现封闭值的大小与实钻圈闭的油柱高度具有良好的正相关关系,证实了该评价方法在多期伸展型交汇断层封闭性评价中的有效性。     

浩布高矿区复杂地层钻进护壁堵漏技术

介绍了浩布高矿区复杂地层钻进中所采取的护壁堵漏技术措施。根据岩层及孔深情况采用了套管护壁堵漏、冲洗液护壁堵漏、水泥封孔护壁堵漏等措施,在实际工作中均收到了较好的效果。套管护壁堵漏简洁、护壁安全可靠;冲洗液护壁堵漏所用的人工钠土低固相泥浆对孔内坍塌、掉块具有较高的抑制功能;水泥封孔护壁堵漏效果好。套管护壁堵漏及水泥封孔护壁堵漏为绳索取心使用无固相钻井液钻进创造了条件,能有效地提高钻进效率。施工中根据钻孔实际情况所采取相应的堵漏措施,收到了良好的效果。